Cardiac Rehabilitation, Congestive Heart Failure and CABG
18
JEPonline
Journal of Exercise Physiologyonline
Official Journal of The American
Society of Exercise Physiologists (ASEP)
ISSN 1097-9751
An International Electronic Journal
Volume 6 Number 1 February 2003
Clinical Exercise Physiology
COMPARISON OF CHANGES IN EXERCISE TOLERANCE AND QUALITY OF LIFE
BETWEEN CONGESTIVE HEART FAILURE AND CORONARY ARTERY BYPASS
GRAFT PATIENTS FOLLOWING A HOSPITAL-BASED CARDIAC REHABILITATION
PROGRAM
CRAIG BRUBAKER1, E. LEA WITTA2, THEODORE J. ANGELOPOULOS3
1
Cardiopulmonary Wellness Manager, Florida Hospital Fish Memorial; 2Associate Professor, Educational
Research, University of Central Florida; 3Professor & Director, Exercise Physiology Laboratory, Child, Family,
and Community Sciences, University of Central Florida
ABSTRACT
COMPARISON OF CHANGES IN EXERCISE TOLERANCE AND QUALITY OF LIFE BETWEEN
CONGESTIVE HEART FAILURE AND CORONARY ARTERY BYPASS GRAFT PATIENTS
FOLLOWING A HOSPITAL-BASED CARDIAC REHABILITATION PROGRAM. Craig Brubaker, E. Lea
Witta, Theodore J. Angelopoulos. JEPonline. 2003;6(1):18-23. Few studies have compared cardiac
rehabilitation program outcomes between individuals with congestive heart failure (CHF) and post coronary
artery bypass graft (CABG), perhaps due to the lack of insurance reimbursement for a CHF diagnosis.
Therefore, we examined the exercise tolerance and quality of life outcomes for 56 individuals with CHF
(age=739 yrs; ejection fraction=3411%) and 52 individuals post CABG (age=737 yrs; ejection
fraction=5710 %) following a 12-week cardiac rehabilitation program, respectively. Both groups exercised a
minimum of 24 sessions over 12-weeks while attending up to 12 educational seminars. Pre- and post- exercise
tolerance was measured by a graded treadmill test and quality of life was assessed using the SF-36 Health
Survey. Following the 12-week cardiac rehabilitation program there were significant improvements in exercise
tolerance in individuals with CHF (16361 to 25170 s; p<0.01) and CABG (20862 to 30990 s; p<0.01). All
nine quality of life constructs improved significantly (p<0.01) within both groups. There were no significant
differences in exercise tolerance or quality of life between groups (p=0.17). Furthermore, a positive and
significant correlation was found between exercise tolerance and patient perceived physical function (R2=0.34,
p<0.01). The data presented in this study suggest that patients with CHF can safely benefits from cardiac
rehabilitation and that their outcomes are similar to patients post CABG.
Key Words: SF-36, Treadmill testing, Cardiomyopathy, Left ventricular dysfunction
Cardiac Rehabilitation, Congestive Heart Failure and CABG
19
INTRODUCTION
Congestive heart failure (CHF) afflicts 4.7 million Americans while accounting for about 7% of the total cost of
heart disease each year (1). Poor physical condition, emotional distress, and frequent hospital admissions
contribute to a decreased quality of life (QOL) among individuals with heart failure (2,3) which can lead to
social impairments, depression, and psychological disorders (4,5).
Most major insurance companies do not reimburse cardiac rehabilitation for individuals with CHF despite their
high hospital readmission rate. However, programs providing a multidisciplinary educational approach have
shown to increase the QOL (6) of individuals with CHF, while also improving physical functioning (7-10).
Interestingly, when these exercise programs are offered on an outpatient basis in hospitals, individuals have
demonstrated a high level of compliance while making significant improvements in exercise tolerance and
muscular strength (11). Furthermore, these documented benefits in quality of life can occur in as a result of
cardiac rehabilitation programs in as little as eight to twelve weeks (12,6).
Perhaps due to the lack of insurance reimbursement for a CHF diagnosis in cardiac rehabilitation programs,
there has been limited research comparing outcomes between individuals with CHF and other forms of heart
disease. Thus, the purpose of this research was to determine if increases in quality of life and exercise tolerance
differ in individuals with CHF or coronary artery bypass graft (CABG) following 12-weeks of cardiac
rehabilitation.
METHODS
Patient Selection
Florida Hospital Fish Memorial is a 97 bed acute care hospital that offers both inpatient and outpatient cardiac
rehabilitation services and follows the guidelines required by an American Association of Cardiovascular and
Pulmonary Rehabilitation Certified program. Thus, the cardiopulmonary wellness staff provides inpatient
education to those individuals with symptoms of CHF and other forms of heart disease prior to their hospital
discharge.
Individuals recovering from a CABG are routinely entered into the cardiac rehabilitation program with a
physician referral and insurance reimbursement. However, individuals discharged with a primary discharge of
CHF, indicated by an ICD/9 code of 428.0, were recruited for this study by offering a free 12-week cardiac
rehabilitation program, pending specific exclusions. Exclusions for the CHF outpatient program included
ejection fraction greater than 45%, discharge to a skilled nursing facility, a pre-transplant individuals,
individuals or physician refusal, hospice patient, individuals receiving dialysis, a previous or scheduled CABG,
or a primary ICD/9 diagnosis code other than 428.0. Exclusions for individuals with CABG this study included
an ejection fraction less than 45%, a co-morbidity of CHF, a primary diagnosis code indicating treatment other
than bypass surgery, or patient refusal.
Data Collection
Physician referral was obtained prior to participation and the Wellness Staff directed any patient care questions
to each respective office during the program.
Following an initial nursing assessment of individuals with CHF and CABG, subjects underwent a graded
treadmill test designed to measure exercise tolerance. The American College of Sports Medicine Guidelines for
Exercise Testing (13) was used for indications and contraindications to treadmill testing. All subjects wore a
telemetry monitor during the treadmill test to measure rate and rhythm based on lead II. Subjects began each
treadmill test by gently holding onto the rails and walking at 1.0 mi/hr with 0% elevation and progressed
through a protocol of increasing speed by 0.5 mi/hr and incline by 1.0% after each one-minute stage. The speed
Cardiac Rehabilitation, Congestive Heart Failure and CABG
20
in stage six terminally increased to 3.2 mi/hr but elevation continued to increase 1.0% each minute. Vitals and
RPE (rate of perceived exertion) were reported at the end of each stage or whenever the patient felt a change in
RPE.
Treadmill test endpoints included reaching 80% of their maximum predicted heart rate, as determined by 220age, and/or a 15 (hard) on the 6-20 RPE scale.13. Exercise tolerance time was determined by the total seconds
completed.
Subjects completed a SF-36 Health Survey® (14) pre- and post-program to determine their physical and mental
QOL constructs. Physical constructs included physical functioning, role-functioning physical, bodily pain, and
general health. Mental constructs included role-functioning emotional, social functioning, vitality, and mental
health, and health transition. All scales were interval/ratio and scored from 0 (worst case) to 100 (best case)
except for health transition, which was measured on a scale of 1 (best case) to 5 (worst case).
All subjects were offered three telemetry monitored sessions/week lasting up to one hour. Every subject was
weighed prior to each exercise session to monitor for possible fluid retention. Cardiovascular exercise
prescriptions were written for 50-70% of maximum heart rate and 11-13 on the RPE scale. To meet a goal of
improved functional capacity, cardiovascular and resistance exercise progression was based on target heart rate,
disease symptoms, and RPE, where duration preceded increases in intensity. Heart rate, blood pressures, and
pulse oximetery were obtained pre- peak and post-exercise. Exercise time was distributed between
Trackmaster® treadmills, Schwinn® stationary bicycles, Monarch® upper body arm ergometers, Nautilus®
resistance equipment, and hand weights.
All subjects were encouraged to attend the 12 weekly education seminars taught by cardiac nurses, respiratory
therapists, and exercise physiologists. The seminars covered topics such as coronary artery disease, dietary
concerns, anatomy and physiology of the heart and lungs, home exercise, risk factors for heart disease, food
label reading, stress management, diabetes, cholesterol, smoking cessation, and medications. Subjects had the
opportunity to ask questions during and after class or in a one-on-one situation with a clinical staff member.
Statistical Analyses
One difficulty associated with testing differences in individuals with heart disease is they start an exercise
program at different stages of progression and cardiorespiratory endurance. Consequently, the naturally
occurring differences between individuals within a group may produce excessive variability thus masking true
gains in score. Repeated measures designs allow a reduction in overall variability by using a common subject
pool for all treatments while allowing removal of subject differences from the error term, leaving the error
components independent from treatment to treatment (15). This procedure is sometimes referred to as using
subjects as their own controls. In addition, the use of multiple tests of statistical significance inflates the error
rejection rate.
To avoid type I error, within and between group pre-post exercise tolerance and quality of life constructs were
examined using a doubly multivariate split plot repeated measures analysis of variance. That is, initially
differences in all quality of life constructs were evaluated simultaneously for between group differences
(between CABG and CHF groups) and within group differences (pre-post scores and interaction of pre-post
score with group). Individual constructs were further examined only if there was an omnibus difference.
A Pearson correlation was used to measure the strength of the relationship between change in exercise tolerance
and the change in self-reported SF-36 Health Survey physical functioning score. A significance level of p<0.05
was considered significant for all outcomes. All continuous data are expressed as meanstandard deviation.
Cardiac Rehabilitation, Congestive Heart Failure and CABG
21
RESULTS
Baseline demographics for individuals with CHF and post CABG
completing the cardiac rehabilitation program in 2000 and 2001 (24
sessions) were similar and are shown in Table 1. Cardiac rehabilitation
was well tolerated for both groups with no untoward events occurring
during the 12-week program. Pre-post changes for exercise tolerance
and quality of life constructs within and between groups are shown in
Table 2. Quality of life scores and exercise tolerance in both groups
improved significantly statistically with the cardiac rehabilitation
program explaining 62% of the variance (F(9,98)=17.9 p<0.001). There
was no statistically significant interaction between the CHF and CABG
groups (F(9,98)=1.47, p=0.17). In addition, exercise tolerance and the
self-reported SF-36 physical functioning (PF) quality of life construct
were significantly correlated for both CHF and CABG patients (r2=0.34,
p<0.01).
Table 1. Patient Characteristics
CHF
CABG
56
52
n
36
29
Male
20
23
Female
§
EF %*
3411
5710
Age (yrs.)
739
737
n Number of participants completing
program (>24 sessions in 12-weeks)
*
Ejection Fraction
§
Values in meanstandard deviation
Table 2. Outcomes for QOL Constructs and Exercise Tolerance µ
CHF
CABG
Outcome
MeanSD
Pre-test
12-weeks
n=
Body Pain**
General Health**
Health Transition**
Mental Health**
Physical Functioning**
Role-Functioning Emotional**
Role-Functioning Physical**
Social Functioning**
Vitality**
Exercise Tolerance**
56
5923
491
3.5.2
6917
4220
4244
1530
585
3922
16361
56
6624
5823
2.31.2
7717
5522
6739
3938
8119
5421
25170
MeanSD
Pre-test
12-weeks
52
5427
6318
3.11.2
7117
4321
4543
1734
8020
4419
20862
52
6525
6417
2.41.2
7618
6121
6940
4237
8520
5521
30990
µ
For readability, all numbers rounded to nearest 1.0 except for Health Transition. n Number of
patients completing program (>24 sessions in 12-weeks). SD Standard Deviation. ¥ Exercise
Tolerance measured in seconds. Significant pre-post changes: ** p < .001. * p < .05. Denotes
significance within-groups.
DISCUSSION
This study suggests that a significant improvement in exercise tolerance and QOL constructs can occur equally
for both individuals with CHF and post CABG following a 12-week cardiac rehabilitation program. Both
groups showed significant similar increases quality of life constructs and exercise tolerance from pre to postprogram. Interestingly, in both groups, self-reported patient perceived physical functioning increased linearly
with their improved treadmill test exercise tolerance.
Our outcomes were consistent with previous research studies involving outpatient intervention programs
designed to increase thefunctional capacity (9) and QOL (12) of individuals with CHF. As mentioned earlier,
Cardiac Rehabilitation, Congestive Heart Failure and CABG
22
few studies are available comparing outcomes of individuals with CHF and post CABG following a cardiac
rehabilitation program. However, one observational study similar to ours in sample size and study design found
equal improvements between individuals with and without left ventricular dysfunction in the six-minute walk
distance and quality of life scores (16). Studies such as these are necessary and serve as an important indication
that individuals with CHF can safely benefit from cardiac rehabilitation programming while learning lifestyle
modifications that may improve overall health. Although there may never be complete restoration of predisease physical functioning levels in individuals with CHF, these initial increases, if sustained, may be
meaningful in terms of the quality of a potentially prolonged life span.
Individuals with CHF have plenty to gain from exercise, so it should be included in their treatment regimen.
However, we feel it is important to employ a symptom–limited exercise test prior to starting the exercise
program, as most individuals are sedentary prior to program entry. Although it may not be safe for all
individuals with CHF to exercise, a safe beginning target heart rate zone is 40-60% of maximum. It is also
important to note that many individuals with CHF have a high resting heart rate, which should be considered
when calculating the target heart rate.
In our program we used three to five minute warm-ups to facilitate vasodilation before increasing into the
higher intensity and longer duration of the exercise prescription. Our CABG ssubjects walked or rode a
stationary bicycle in their target heart rate zone for 20 to 40 min two to three days/week with little unusual
fatigue. However, when needed, we employed interval training for individuals with CHF to build their
endurance slowly without discouraging them from returning to the program. Alternating activity with rest,
closely resembles the demands of their daily life so we generally started interval training with one to two
minutes of rest, until they could complete 15 to 20 min of exercise.
We feel it is important to teach all individuals about their medications, the signs of angina, decompensation,
oxygen desaturation, and water retention to assist in their own healthcare. To this point, clinicians should not
be apprehensive about discussing appropriate regimens with the individual’s primary physician or specialist.
Limitations
A limitation of this study is the lack of a control group for comparison to treatment withheld. We also were not
able to use a maximal stress test with gas exchange analysis for measuring actual maximal functional capacity.
However, we believe that our treadmill test was useful within its parameters in measuring the actual increases in
exercise tolerance, verified by the subjects in their SF-36 physical functioning QOL construct score. In
addition, this efficient and inexpensive graded treadmill protocol can be implemented in any cardiac
rehabilitation facility to provide a baseline for exercise tolerance.
Conclusion
Large, randomized studies are needed to accurately assess the impact of long-term exercise therapy on CHF
morbidity and mortality rates, maintenance of functional capacity and quality of life. Currently, we are
examining if these short-term outcomes can be sustained for a longer period of time in the individuals with
CHF. In addition, hospital-based cardiac rehabilitation programs may also find they can increase program
revenue by safely integrating individuals with CHF into their maintenance programs. In conclusion, the data
presented in this study suggest that major insurance companies may want to consider reimbursing cardiac
rehabilitation programs for individuals with CHF, or with left ventricular dysfunction (ejection fraction < 45%)
as they do with other diseases of the heart.
Address for Correspondence: Craig Brubaker, FLORIDA HOSPITAL Fish Memorial, Cardiopulmonary
Wellness Center, AACVPR Certified Program, 1055 Saxon Blvd., Orange City, FL 32763; Phone: (386) 9175125 ; FAX: (386) 917-5167; Email: craig.brubaker@fhfm.org
Cardiac Rehabilitation, Congestive Heart Failure and CABG
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